Circulatory System Cardiovascular system function: Three basic components Heart Blood vessels Blood Cardiovascular system function: Transport oxygen Nutrients Cell wastes Hormones via the blood

Cone shape Muscular pump 250 – 300 g Size of a person’s fist

Location Mediastinum Superior surface of diaphragm Anterior to the vertebral column Posterior to the sternum Apex is directed toward the left, rests on the diaphragm, at about the fifth intercostals space

Pericardium

Pericardium : The pericardium: A superficial fibrous pericardium A deep two-layer serous pericardium The parietal layer The visceral layer They are separated by the fluid-filled pericardial cavity The pericardium: Protects Prevents overfilling Allows for the heart to work in a relatively friction-free environment

Heart Wall Epicardium – visceral layer of the serous pericardium Myocardium Endocardium

Anatomical position surface Borders Base Apex Sternocostal Diapgragmatic Pulmonary R &L Borders Left Right Inferior superior Base Apex

Four hollow chambers: 2 atria – receiving chambers divided by the interatrial septum 2 ventricles – discharging chambers divided by the interventricular septum

Atria Septum Ventricles

Anterior Inter ventricular sulcus Sternocostal surface Left Atrium Left Ventricle Right Atrium Sinus coronary sulcus Anterior Inter ventricular sulcus Right Ventricle

posterior Inter ventricular sulcus Diaphragmatic surface Left Ventricle posterior Inter ventricular sulcus Coronary Sulcus

Right atrium Ineratrial septum Fossa ovalis Right auricle Superior Vena Cava inferior Vena Cava Coronary sinus Right atrioventricular foramen

Pectinate Muscle Fovea Ovalis

Blood Enters The Right Atrium Via Three Veins Superior vena cava Superior vena cava Inferior vena cava Coronary sinus Coronary sinus Inferior vena cava

Right ventricle Right ventricle: Papillary muscles Papillary muscles Chorda tendineae Tricuspid valves Pulmonary artery Right ventricle: Papillary muscles Chorda tendineae Tricuspid valves Pulmonary artery Trabeculae carneae

Chordae tendoneae Papillary muscles

Left atrium Left auricle Left atrioventricular foramen Aorta foramen

Blood enters the left atrium via four veins Right and left pulmonary veins Right Pulmonary veins Left pulmonary veins

Left ventricle Left ventricle Papillary muscles Chorda tendineae bicuspid valves Aorta Papillary muscles Chorda tendineae Bicuspid valves Aorta

Radiographic Landmarks

Major Vessels of the Heart Vessels returning blood to the heart include: Superior venae cavae inferior venae cavae Right and left pulmonary veins Vessels conveying blood away from the heart include: Pulmonary trunk Ascending aorta

Valves of the Heart Atrioventricular valves Semilunar valves Right AV (Tricuspid) Left AV (Bicuspid) Pulmonary valve Aortic valve

Pulmonary semilunar valve Right AV (tricuspid) valve Aortic semilunar valve Chordai tendineae Papillary muscle Left AV (bicuspid) valve

Pathway of Blood

Circulatory System Pulmonary circulation Systemic circulation

Pathway of Blood Through the Heart and Lungs RA  tricuspid valve  RV RV  pulmonary semilunar valve  pulmonary arteries  lungs Lungs  pulmonary veins  LA LA  bicuspid valve  LV LV  aortic semilunar valve  aorta Aorta  systemic circulation

Pulmonary Circulation

Systemic Circulation

Intrinsic conduction system ( Nodal system )

Two systems act to regulate heart activity: Extrinsic conduction system 2. Intrinsic conduction system = or nodal system Setting the basic rhythm Sinoatrial (SA) node : located in right atrium pacemaker of the heart Atrioventricular (AV) node : at junction of atria and ventricles Atrioventricular (AV) Bundle (Bundle of his) Bundle branches Purkinje fibers

Bundle of His SA Node Internodal Pathways Bundle Branches Purkinje Fibers AV Node

Regulation of Heart Rate Increased heart rate Sympathetic nervous system thoracic N – 1- 4 Low blood pressure Hormones Epinephrine Thyroxine Exercise Decreased blood volume Decreased heart rate Parasympathetic vagus N High blood pressure or blood volume

Heart Sounds

Murmurs = abnormal heart sounds Lub dup Lub – closing of AV valves ( systole ) Dup – closing of semilunar valves (diastole ) Murmurs = abnormal heart sounds

Cardiac Cycle Systole : lup Rising ventricular pressure results in closing of AV valves Atria relax Diastole : dup relaxation of heart muscle

Blood Vessels

Capillary Beds Figure 19.4a

Blood Pressure (BP) Systemic pressure: Force wall of a blood vessel by its contained blood Expressed in millimeters of mercury (mm Hg) in large arteries near the heart Systemic pressure: Is highest in the aorta Declines throughout the length of the pathway Is 0 mm Hg in the right atrium

Measuring Blood Pressure first sound heard = systolic pressure Second sound heard = diastolic pressure Systole = contraction Diastole = relaxation

Blood Pressure: Effects of Factors Normal 140–110 mm Hg systolic 80–75 mm Hg diastolic Hypotension Low systolic (below 110 mm HG) Hypertension High systolic (above 140 mm HG) Neural factors (sympathetic division) Renal factors ( Renin ) Temperature Heat has a vasodilation effect Cold has a vasoconstricting effect Chemicals Various substances can cause increases or decreases Diet

Cardiovascular Disease

Types Of Cardiovascular Disease Atherosclerosis ----(Plaque ) Coronary heart disease (CHD) ---Myocardial infarction (MI) or heart attack Chest pain (angina pectoris) Ischemia Irregular heartbeat (arrhythmia) Tachycardia = more than 100 beats/min Bradycardia = less than 60 beats/min Congestive heart failure (CHF) heart muscle is unable to keep blood circulating normally Congenital heart disease Stroke--- Myocardial infarction (MI) Embolism: blockage of blood vessels

Common Blood Vessel Disorders

Angioplasty Versus Bypass Surgery Coronary bypass surgery

Inflammation of pericardial sac Pericarditis Inflammation of pericardial sac Clinical Manifestations of Pericarditis Chest pain Dyspnea Chills Fever Pain –Substernal, over heart, can radiate, intense sharp grating pain that increases with deep inspiration, coughing, lying flat. Relieved by sitting up, leaning forward Pericardial rub produced from the inflamed pericardial and epicardial layers rubbing together with movement. Can be intermittent. Pericardial effusion – abnormal amount of pericardial fluid, if develops gradual as much as 400 ml can accumulate before there is an effect, but if it is rapid, not time to adjust and will see effects with as little as 100ml. It can impede functioning of heart – cardiac tamponade. Signs of pericardial effusion – dyspnea as tissue becomes depressed, distant heart sounds, tachycardia. As it progresses, tamponade can occur – cardiac output falls, BP falls, restlessness, confusion, tachycardia, paradoxical pulse – drop in SBP of more than 10 mmHg with inspiration.

Clinical Manifestations of Mitral Stenosis Cough Frequent respiratory infections Weakness, fatigue Diastolic murmur Murmur heard best at the apex of the heart-low pitch rumbling

Varicose Veins